Magneto-actuating mechanism



P. BROWN MAGNETO ACTUATING MECHANISM Spt. 27. 1921. 1,643,636

FiIed April 28, 1924 .17 at a J? C I. an. no U l j ,1 INVENTOR ATTORNEYS Patented Sept. 27, 1927.

"UNITED STATES PHELPS BRQW'N, or SP INGFIELD,'MAssAcnUsnTrs.

MAGNETO-ACTUATING MECHANISM.

' Application filed April 28,

This invention relates toimprovements in armature actuating mechanism for magnetos of the so-called sliding armature type.

Une example of a magneto of this generaltype will be found in U. S. Letters Patent No. 1,489,382, granted April 8,1924, 'on an invention of Phelps Brown and Harold H. Clark. I I ,f I

The general object of thisinvention is to provide a generally simplified and improved means for operating-the armature, of a magneto. of the general type referred toabove, from the push rod of an internal combustion engine. 1

Other objects and advantages will appear is the following descri tion and in the illustrative embodiment 0 the invention in the accompanying drawings, in -which-:- I

Fig. 1 isa small scale elevational view showing the application of a magneto, and the armature actuating mechanism of this invention, to an internal combustion engine;

Fig. 2 is an enlarged fragmentary elevational viewthereof showing the armature actuating mechanism in full detail;

Fig. 3 is a cross sectional view taken on the line 3-3 of Fig. 2; and

' Fig. 4 is a sectional plan view taken on;

the line H of Fig. 3.

Referring to these drawings; an internal combustion engine isconventionally represented at E,-in Fig. 1', and M represents a magneto, suitably supported therefrom adjacent the push rod a of the engine. Push rod a is mounted to slide horizontally beneath the magneto and its ordinaryfunction is to control the opening and closing of the exhaust valve, which it accomplishes through the usual rocker arm I pivotally supported at c from a bracket d fixed to the cylinder head of the engine. Rod a is supported and guided at one end in bracket (Z and at the other end has an extension (1 which is guided by the cam shaft e, being slotted, as at f, to straddle the latter. Fixed on shaft 6 is a-suitable cam g, the periphery of which is engaged by a roll it carried by rod a. The roll is held in contact withcam g by means of a spring z' acting between bracket d and an abutment j fixed on rod a. The cam shaft 6 is drivenby gearing 71: from the crankshaft; of the engine, at the proper speed relative thereto, in the usual manner. 7 a 1 j In the example illustrated, the engine is of 'tllE-"fl'illl cycle typeand cam shaft 6 rm "operate the armature o, a

1924. Serial. No. 709,624.

tates at one half the crankshaft speed. The relative positions of the'parts shown inFig. l are those which obtain at the beginning of the compre-si0n stroke. Thehigh point of the cam is shown'atm and, when thisporat substantially the beginning of the firing stroke,the exact time of operation being variable within hm-lts as will later 'be described. Therev is sufficient clearance, as

shown at 0, between the push rod a and rocker arm 5 so that the latter'is not engaged and moved during that movement of push rod a which is effected by the rise In of cam g. Y

The magneto M is provided with an armature 5 which is slidable in a straightline towardv and away from the ends of a pair of magnetic cores or pole pieces 6.. As shown, the armature slides in a vertical path on a fixedgulde pin 7. The armature is arranged, when inone position (that'shown in Fig. 1), to contact with both poles 6 and connect the same and, when moved away from this position, to generate the ignition spark during its downward flight. Thedetails of the magneto are not essential to an understanding of this invention but for a full disclosure of the particular magneto shown reference may be had to the copending application of Phelps Brown and Terrence G. Louis, Serial No. 652,356, filed July '18, 1923. v

' The armature actuating mechanism con sists of a few simple and inexpensive parts mounted directly .on the push rod on in a simple manner. I

bell crank lever 8 is pivotally mounted intermediate its ends onastud 9 carried by the magneto frame'lO. One arm of the lever 8 is providedwitha forked extremity which fits between the depending arms of a fork 11, fixed to armature 5, and straddles the stud 12 which connects such arms. The otherarm of lever, 8 is likewise forked, as at 13, to straddle the push rod The armature drive spring consists To enable these parts to i and fork 18.

'On movement of push rod to the left (as viewed in Fig. 1), the drive spring 1 1 is compressed between the abutment and fork 13, the latter remaining stationary due to the magnetic hold on armature 5.

and fork 13.

to which it may be moved.

- time relative to the engine cycle.

The latter is held by magnetic attraction to cores 6 by a force which is superior to that of drive spring 14 even when fully compressed and, as in the Brown and Clark patent above identified, it is necessary to break this magnetic 'hold before the stressed drive spring can function" to move the armature. The magnetic hold is broken by an inelastic transmission of force from push rod a which in this particular case is effected by a sleeve 19 which encompasses rod or and is disposed within spring 14 and between abutment 15 That end face of sleeve 19 adjacent fork 13 may be termed a trip shoulder for, when it engages the washer 16, after the stressing of spring 1 1, it breaks the magnetic hold on the armature and allows spring 14: to expand and rapidly move the armature. The shoulder, ref-erred to, is therefore a trip since it controls the time at which the armature leaves its poles. In Fig. 2, the parts are shown in the relative positions which obtain at the instant of the tripping of the armature.

To vary this time, an advance lever 20 is provided which, as best shown in Fig. 3, is pivotally connected to the fork 13. The

; pivot consists of a cap screw 21 between the head of which and lever 20 a, spring washer 22 is applied to produce a friction on the lever and releasably hold it in any position Lever 20 has a curved slot 23 to receive rod a and permit a part of the lever to be interposed between washer 16 and fork 13, thereby virtually increasing the thickness of the fork and causing it to be engaged by sleeve 19 at an earlier The lever 20, in those parts adjacent the entrance to slot 23, is bevelled, as at 24, to permit it to be readily interposed between the described parts. In normal operation, the lever 20 is interposed between said parts but, at starting, it is withdrawn to effect retarded lgnition.

In operation, the push roda moves toward the left from the illustrated position durin the compression stroke of the engine and .6 to produce the ignition spark.

adapted for convenient installation. rocker arm 7) is removed, collar 7 loosened during this movement the drive spring 14 is compressed and thereby placed under stress for its subsequent armature driving function. At or near the end of the compression stroke, or early in the firing stroke if lever 20 is not interposed as described, the sleeve 19 effects a preliminary movement of fork 13" and causes the magnetic hold on the armature to be broken, which action is followed by. an expansion of drive spring'l l, whereby the armature is moved rapidly away from cores The movement .ofarmature 5 by the drive spring is at a rate considerably greater than that of push rod w and the return spring 17 is lighter than spring 1 1 and yields to permit the necessary travel of fork 13 during the action described.

After ignition, the-fpush rod continues to travel in the same direction and moves the fork 13, and with it the armature, a still further distance and compresses the return spring 17. Eventually the push rod engages rocker arm band causes the exhaustfvalve to open, after which the push rod moves back under the act-ion of spring During the return movement of 'the push rod, the fork 13 is moved back into the illustrated position and the armature again seated on its cores 6,

after which sleeve 19 moves away from fork 13. Preferably, the push rod a moves to the right farenough'to create a small clearance between the'unstressed drive spring let and'fork 13, whereby the lever 20 may read ily be interposed at this time. k

The driving mechanism not only consists of a relatively few simple parts but it is also The and the extension 0 unbolted from push rod (0, after whichthe latter can be pulled to the left sufficiently to allow the spring 17, washers 18 and 16, sleeve 19, spring'lt' and collar 15 to be slipped onto the rod in the order named. The push rod is then pushed back and bolted tOBXtQIlSlOH a after which rocker arm I) is applied in place. The frame 10 which supports an parts of magneto M, in-

eluding bell crank lever 8', is then bolted to the engine in a suitable location so that fork 13 straddles the push rod a and is interposed between washers 16 andlS. After'this the collars 15'and are adjusted on roda and fixed thereto'in the proper location.

The invention has been disclosed herein, in an embodiment at present preferred, for illustrative purposes but the scope of the invention'is defined bythe appended claims rather than by the foregoing description. Claims:

1. The combination with a magneto having an armature and a lever for operating the same, of a reciprocable member slidable relatively thereto, and a pair of springs carried by said member between the free ends of which a portion of said lever is received.

ingan arn'iajture and a lever for operating the same, of a reciprocable member with which saidjle'ver is loosely engaged, a slroul- (let provided on said member to engage and move said lever'in one direction, and spring carried by said member for moving the lever in the other dir'cctioi'ij' 3,.The combination, with a reciprocable member of an internal combustion engine, of magneto supported adjacent said member and provided with magnetic poles and an armature movable into and out of contact therewith, a drive spring for the armature coiled around said member, an abutment on the latter to engage one end of said spring, means to move the armature and having a part arranged in the path of'the other end of said spring, a shoulder carried by the push rod and operable after said spring has been compressed to a predetermined degree between said abutment and part to engage the latter and break the magnetic hold between thearmature and its poles,. allowing the previously compressed drive spring to expand and rapidly move the armature away fromits poles, and spacing means adapted to be interposed between said shoulder and part when desired.

4. The combination with a reciprocable .member of an internal combustion engine, of a magneto supported adjacent said member and provided with magnetic poles and an armature movable toward and away from the same, a drive spring for the armature coiled around said member, an abutment on the latter toengage one end of said spring, means to move the armature and having a part arranged in the path of the other end of said spring, and a shoulder carried by the push rod and operable after said spring has been compressed to a predetermined degree between said abutment and part to engage the latter and break the magnetic hold between the armature and its poles, allowing the previously compressed drive spring to expand and rapidly move the armature away from its poles.

5. The combination with a reciprocable member of an internal combustion engine, of a magneto supported adjacent said member and provided with magnetic poles and an armature movable toward and away from the same, a drive spring for the armature coiled around said member, an abutment on the latter to engage one end of said spring, means to move the armature and having a part arranged in the path of the other end of said spring, a shoulder carried by the push rod and operable after said spring has been compressed to a predetermined degree between said abutment and part to engage the latter and break the magnetic hold between the armature and its poles, allow ing the previously compressed drive spring to expand andimpidiy moveathe a rih i away from its poles,and an armature turn spr ng coiled around saidmember and acting on said part ine posinoato said drivespring;

" The 'eoi'nbi'nation with the, reci rocable push rod of an internal combustion engine,

"of a 'magne'to supported adjacent said and having an armature slidable in a path at an anglet'o that of said-rod, an abutment fixed to said rod. a spring encircling the latter and engaging at one'end ,Wlth said abutment, a pivoted lever having a part engaged to move the armature and a part disposedin the path of the other end of said spring and adapted to be engaged't hereby on mavement of the push rod, and a shoulder on the latter adapted after said spring has been compressed to a predetermined degree bemtween said abutment and last named part to engage the latter and cause the armature to be preliminarily moved by an inelastic transmission from the push rod;

7. The combination with the reciprocable push rod of an internal combustion engine,

of a magneto supported adjacent said rod and having an armature slidable in a path at an angle to that of said rod, a pivoted lever having a part engaged to move the armature and a forked part to straddle said rod abutments on the latter one on each side of said last named part, an armature drive spring acting between one abutment and one face of said last named part, an armature return spring acting between the other abutment and the opposite face of the last named part, and a shoulder on the push rod arranged to engage the latter after the drive spring has been compressed to a predetermined degree by movement of the push rod to effectthe preliminary movement of the armature by an inelastic transmission from saidpush rod.

8. The combination with an internal combustion engine, having a valve-actuating push rod reciprocable in a horizontal path, a magneto supported adjacent thereto having an armature movable into and out of contact with the magnetic poles thereof and slidable in a vertical path, a bell crank lever pivoted intermediate its ends and having one arm engaged with the armature to move the same, the other arm of said lever having a forked end to straddle said rod, a drive spring and a return spring for the armature both encircling said rod and disposed on 0pposite sides of said end, ab'utments on the rod one for each spring, and a shoulder carried directly by said rod and a'daptedvto engage said end after the drive spring has been compressed between its abutment and said end.

9. The combination with an internal com bustion engine having a reciprocable push rod, of a magneto supported adjacent thereto and having a movable armature, a pivoted lever connected to move said armature, two

longitudinally spaced abutments on said push rod, discs slidable on the latter bepart disposed between said discs, and a sleeve on said rod arranged between one abutment and the adjacent disc and adapted to engage the latter after the adjacent spring has been compressed.

1.0. The combination with an internal combustion engine having a reciprocable push rod, of a magneto supported adjacent thereto and having a movable armature, a pivoted lever connected to move said armature, two

longitudinally spaced abutments on said push rod, discs slidable on the latter bet-ween said abutments, springs encircling said rod and disposed one between each abutment and the adjacent disc, said lever having a part disposed between said discs, a sleeve on said rod arranged between one abutment and the adjacent disc and adapted to engagethe latter after the adjacent spring has been compressed, and a spacing member pivoted to said lever and adapted to be interposed between said sleeve and part, when desired.

In testimony whereof I have affixed my signature.

PHELPS BROWN. 

